[PATCH v3] net: mlx5: Add a missing check on idr_find, free buf

[Aditya Pakki]

idr_find() can return a NULL value to 'flow' which is used without a check.
The patch adds a check to avoid potential NULL pointer dereference.
In case of mlx5_fpga_sbu_conn_sendmsg() failure, free buf allocated
using kzalloc.

---
v2: failure to return in case of flow failure.
v1: Failed to free buf in case of flow failure.

Signed-off-by: Aditya Pakki <pakki001@xxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
index 5cf5f2a9d51f..224e0d7f6489 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
@@ -226,6 +226,11 @@ int mlx5_fpga_tls_resync_rx(struct mlx5_core_dev *mdev, u32 handle, u32 seq,
 	rcu_read_lock();
 	flow = idr_find(&mdev->fpga->tls->rx_idr, ntohl(handle));
 	rcu_read_unlock();
+	if (!flow) {
+		WARN_ONCE(1, "Received NULL pointer for handle\n");
+		kfree(buf);
+		return -EINVAL;
+	}
 	mlx5_fpga_tls_flow_to_cmd(flow, cmd);
 
 	MLX5_SET(tls_cmd, cmd, swid, ntohl(handle));
@@ -238,6 +243,8 @@ int mlx5_fpga_tls_resync_rx(struct mlx5_core_dev *mdev, u32 handle, u32 seq,
 	buf->complete = mlx_tls_kfree_complete;
 
 	ret = mlx5_fpga_sbu_conn_sendmsg(mdev->fpga->tls->conn, buf);
+	if (ret < 0)
+		kfree(buf);
 
 	return ret;
 }
-- 
2.17.1